JP5626216B2 - Flame retardant polyester composite film - Google Patents

Description

  The present invention relates to a flame retardant polyester composite film. The present invention is an application claiming priority based on US Provisional Patent Application No. 61/107218 filed Oct. 21, 2008.

  Polymer films such as polyester films are used in various nearly infinite fields. For example, the film is used as a packaging material, as a label, as a release liner, as an optical filter, as a laminate on furniture, as a window treatment member such as a blind or a sunshade. Polymer films are also used in electronics, for example, as members that wrap cables and wires.

  For certain applications, it is desirable for the polymer film to be flame retardant. For example, Patent Document 1 (Ye et al.) Discloses a metallized flame-retardant polyester film, which is cited by reference in the present invention, but various concentrations of phosphorus-based flame retardants are added to individual film layers. ing. Patent Document 2 (Kiehne et al.) Discloses adding various flame retardants to a multilayer biaxially stretched polyester film.

  Although various flame retardant films have been disclosed so far, further improvements are required.

US Patent Application Publication No. 2006/0110613 US Pat. No. 7,189,451

  In view of the above, the present disclosure aims to provide further improvements in the construction of flame retardant films, particularly flame retardant polyester films.

Typically, the present disclosure relates to a flame retardant composite film that includes different flame retardants, and due to their synergistic effects, films having excellent flame retardancy can be produced.

In some embodiments, for example, the composite film consists of three layers. For example, the composite film has a first film layer and a third film layer, each consisting of a polyester polymer. At least one or both film layers may have a first flame retardant. The composite film may have a second film layer (intermediate film layer) disposed between the first film layer and the third film layer. The second film layer is made of a polyester polymer containing a second flame retardant. Unlike the first flame retardant, the second flame retardant is composed of a volatile decomposable flame retardant. Here, the “volatile decomposable flame retardant” means a flame retardant that generates a volatile decomposition product when the polymer is heated and melted. Particularly, when the polymer is heated to 175 ° C. or more, acetaldehyde or the like It means a flame retardant that generates a small amount of aldehyde. By disposing the volatile decomposable flame retardant in the intermediate layer, the volatile decomposition product remains trapped in the composite film and still imparts excellent flame retardancy to the composite film.

  In one embodiment, the first flame retardant and the second flame retardant are organophosphorus compounds chemically bonded to a polyester polymer. For example, a first flame retardant and a second flame retardant are incorporated into the main chain of the polyester polymer and exist as pendant groups.

  In certain specific embodiments, the first flame retardant is bis (2-hydroxyethyl) [(6-oxide-6H-dibenzo- [c, e] [1,2] oxaphosphorin-6-yl) methyl. It may consist of butanedicarboxylate. The second flame retardant may consist of a phosphorus compound ester.

  When the first flame retardant and / or the second flame retardant is made of a phosphorus compound, the concentration in each film layer is 5000 ppm or more. For example, the flame retardant is added to the individual film layers so that the phosphorus concentration is about 5000 to 20000 ppm, preferably about 7000 to 12000 ppm.

The thickness of the flame retardant composite film can be an appropriate thickness in the field of use. In certain embodiments, for example, the thickness of the composite film is about 0.5-7 mil, preferably about 1-2 mil. The weight of the first film layer and the third film layer is about 5 to 40% by weight, preferably about 10 to 20% by weight, respectively, of the weight of the composite film. The weight of the second film layer is about 20 to 90% by weight, preferably about 60 to 80% by weight of the composite film. The thickness of the second film layer is about 0.5-7 mil, preferably about 1-2 mil.

The polyester polymer that forms the polymer film may comprise a preferred polyester such as polyethylene terephthalate. In certain embodiments, the three film layers may be coextruded together. In this embodiment, for example, there may be no intermediate film layer between the intermediate film layer and the outer first and third film layers. When coextrusion is performed, the formed film can be stretched in at least one direction. For example, the composite film can be biaxially stretched. When forming a film layer via extrusion, each polymer resin used to form the film layer may have an intrinsic viscosity of about 0.60 to 0.68 (IV).

  In some embodiments, a metal layer or metal oxide layer may be adhered to the flame retardant composite film. When the metallized layer is present in the composite film, for example, the final product is particularly suitable as window blinds, window shades, and other window processing members.

  In certain embodiments, the composite film disclosure of the present invention is initially formed from only two film layers. In this embodiment, the first film layer contains a first flame retardant, the second film layer contains a second flame retardant, and the second flame retardant comprises a volatile decomposable flame retardant. In this embodiment, two film layers may be introduced into other configurations. For example, the second film layer may be coated with a coating such as a metallized coating to contain the volatile decomposable flame retardant.

  In one embodiment, particularly when a window processing member is formed, the above two composite films can be bonded together to form a laminate. A composite film may be laminated together using a flame retardant adhesive. The laminate may have a first outer surface and two outer surfaces. In certain embodiments, the first outer surface may comprise a metallized layer. The second outer surface, on the other hand, can be dyed in a slightly dim color to produce a translucent material with light filter properties.

In other embodiments, filler particles may be added to one or both outer layers (first and third film layers) of the composite film. When filler particles are added to the outer layer, for example, the addition amount is about 5 to 40% by weight. Fillers may be added to the outer layer to produce a colored opaque material. In some embodiments, for example, titanium dioxide particles may be added to one or both outer layers to obtain a white composite film layer.

  Other features and aspects of the invention are described in detail below.

  The flame retardant composite film of the present invention contains different flame retardants and has excellent flame retardancy due to their synergistic effect.

Sectional view of one embodiment of a flame retardant composite film produced according to the present invention Sectional view of one embodiment of a laminate produced in accordance with the present invention A perspective view of one embodiment of a window treatment constructed in accordance with the present invention. A perspective view of another embodiment of a window treatment constructed in accordance with the present invention.

  All and possible descriptions of the invention, including the best mode for those skilled in the art, are described in detail below with reference to the drawings. Repeated use of reference characters in the present specification and drawings shall indicate the same or similar elements or elements of the invention.

  As will be appreciated by those skilled in the art, this description is of an exemplary embodiment and is not intended to limit the broader scope of the invention.

Typically, the present invention relates to a flame retardant composite film. The composite film is composed of a plurality of film layers. In some embodiments, for example, two or more layers comprise a polyester polymer in combination with a flame retardant. In accordance with the present disclosure, the second film layer of the composite film (sometimes referred to as an intermediate film layer or an intermediate layer) contains a flame retardant comprising a volatile decomposable flame retardant. The second film layer is disposed between first and third film layers (sometimes referred to as an outer film layer or an outer layer) disposed on a pair of opposite sides, respectively. One or both outer film layers can also contain a flame retardant, but the flame retardant in the outer layer comprises a non-volatile degradable flame retardant.

  The inventors have found that the intermediate film layer containing the volatile decomposable flame retardant is disposed on a pair of opposite sides, respectively, and is encapsulated between the outer film layer containing the non-volatile decomposable flame retardant. It has been found that unexpected benefits and effects are given. In particular, the flame retardance of the entire composite film is remarkably improved by the configuration of different film layers.

  For example, Underwriters Laboratories, Inc. Publishes standard tests on the flammability of plastic materials, including films. In particular, Underwriters Laboratories, Inc. Published a flammability standard test in the UL-94 operating guide. In particular, UL-94 test 11 relates to a vertical burn test of thin materials.

  According to UL-94 Test 11, thin materials are classified by “VTM” ranking as a flammability criterion for test samples. The polyester film has, for example, a VTM-2 flammability test rank. The composite film of the present invention can have a VTM-0 flammability test rank which is the highest flame retardant level in this test. The VTM-0 flammability test rank refers to a case where, for example, the test sample is fixed with the longitudinal direction of the test sample vertical and the test sample is flamed twice for 3 seconds, and then combustion stops within 10 seconds. The flame is a blue frame about 20 mm above the flame coming out of the burner. The VTM-0 flammability test rank also means that there are no flame particles or fallen objects and the cotton cloth placed under the test sample does not ignite.

  It is believed that achieving the above results is a synergistic effect of the intermediate film layer containing the volatile decomposable flame retardant with the outer film layer containing a different flame retardant. In fact, it has been found that the flame retardancy of the composite film is significantly improved compared to simply encapsulating an intermediate film layer containing a volatile decomposable flame retardant with two outer film layers each containing no flame retardant. . The flame retardancy of the composite film of the present invention is such that the content of the phosphorus compound in the outer layer is higher than that in the innermost layer or the inner layer, and the content of the multilayer film described in U.S. Patent Application Publication No. 2006/0110613. It is something that cannot be imagined from the viewpoint.

FIG. 1 shows, by way of example, a cross-sectional view of a flame retardant composite film 10 according to the present invention. The composite film 10 includes a second film layer 14 between the first film layer 12 and the third film layer 16. However, it should be understood that the composite film 10 may have only two layers or three or more layers. In the embodiment described in FIG. 1, the film layers may be placed directly near each other. In other embodiments, however, other film layers may be disposed between the second film layer 14 and the first film layer 12 and the third film layer 16.

  Each of the film layers 12, 14, and 16 is formed from a thermoplastic polymer. In certain embodiments, for example, each film layer may consist of a polyester polymer. The polyester polymers forming each layer may be the same or different. Examples of the polyester polymer include polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate. Copolyester polymers such as polyethylene terephthalate-isophthalate may also be used. Usually, polyester films based on polymers obtained by polycondensation of glycols or diols with dicarboxylic acids (or ester equivalents) can be used. Dicarboxylic acids include terephthalic acid, isophthalic acid, sebacic acid, malonic acid, adipine Examples thereof include acid, azelaic acid, glutaric acid, suberic acid, and succinic acid, and these may be used in combination of two or more. Examples of preferable glycols include ethylene glycol, diethylene glycol, polyethylene glycol, and polyols such as butanediol. Two or more of these may be used in combination.

In addition to the thermoplastic resin, at least one of the second film layer 14 and the first and third film layers 12 and 16 may contain a flame retardant. In one specific embodiment, for example, both the first and third film layers 12 and 16 contain a flame retardant.

In accordance with the present disclosure, the flame retardant contained in the second film layer 14 comprises a volatile decomposable flame retardant. On the other hand, the flame retardant contained in the first and third film layers 12 and 16 is usually composed of a non-volatile decomposable flame retardant. By maintaining a volatile decomposable flame retardant in the second film layer 14, some volatile compounds such as aldehyde compounds are trapped in the composite film 10 when the composite film is exposed to heat or direct flame. Remain. Maintaining a volatile decomposable flame retardant in the second film layer 14 is believed to increase the performance of the flame retardant and improve the overall flame retardancy of the composite film. For example, in some embodiments, the volatile decomposable flame retardant comprises a phosphorus compound. Maintaining a volatile decomposable flame retardant in the second film layer 14 prevents the release of phosphorus compounds from the second film layer and thus maintains the flame retardancy of the composite film.

As described above, one or both of the first and third film layers 12 and 16 may contain a flame retardant different from the flame retardant contained in the second film layer. The present inventors have found that the flame retardant contained in the outer film layer and the flame retardant contained in the intermediate film layer show a synergistic effect. With this configuration, a composite film having excellent flame retardancy as a whole can be produced. In particular, the composite film of the present invention does not contain a flame retardant in the outer film layer, and has a flame retardant property as compared with a composite film having a similar structure containing a volatile decomposable flame retardant in the intermediate film layer. Remarkably improved.

The flame retardant contained in the first film layer 12 and the flame retardant contained in the third film layer 16 may be the same or different. Preferred examples of the flame retardant include halogen compounds such as organic bromine compounds and organic chlorine compounds, and organic nitrogen compounds. Examples of other flame retardants include metal hydroxides and metal oxide trihydrates.

  The flame retardant contained in the film layers 12 and 16 may be mixed with the constituting thermoplastic polymer, or may be chemically bonded to the polymer. The flame retardant may be chemically bonded to the polymer, for example by covalent bonds. The flame retardant may be chemically bonded to the polyester polymer, for example so as to form a polymer backbone or to be a pendant group.

Particularly suitable flame retardants used for the first and third film layers include phosphorus compounds such as organic phosphorus compounds. Such compounds not only have excellent flame retardancy, but can be chemically bonded to thermoplastic polymers such as polyester. Examples of such flame retardants include carboxyphosphinic acid (including anhydride) and dimethyl methane phosphate. Examples of other phosphorus compounds include various phosphorus compound esters such as butanedioic acid ester. In one preferred embodiment, the butanedioic acid ester is bis (2-hydroxyethyl) [(6-oxide-6H-dibenzo- [c, e] [1,2] oxaphosphorin-6-yl) methyl] butanedi Carboxylate, which is butanedioic acid, [(6-oxide-6H-dibenzo- [c, e] [1,2] oxaphosphorin-6-yl) methyl], bis (2-hydroxyethyl) Also referred to as an ester, it has the following structural formula:

As described above, the intermediate film layer contains a volatile decomposable flame retardant different from the flame retardant contained in the outer layer. The volatile decomposable flame retardant may be made of a phosphorus compound such as an organic phosphorus compound. In one embodiment, for example, the volatile decomposable flame retardant comprises a phosphorus compound-based ester. The volatile decomposable flame retardant may be chemically bonded to a thermoplastic polymer such as a polyester polymer. For example, the volatile decomposable flame retardant may be incorporated into the main chain skeleton of the polymer and covalently bonded to the polyester polymer, or may be incorporated as a pendant group. In one embodiment, the volatile decomposable flame retardant used in the second film layer 14 is available under the trade name “8934H” from Invista. 8934H is composed of a modified polyethylene terephthalate polymer containing a volatile decomposable flame retardant composed of a phosphorus compound. When exposed to flame, the modified polyethylene terephthalate polymer generates a small amount of volatile decomposable material, including acetaldehyde (at about 175 ° C.).

  The amount of flame retardant contained in each film layer depends on various factors including the use of the composite film used. Generally, the amount of flame retardant contained in each film layer is about 0.1 to 5% by weight, depending on the nature of the selected flame retardant. When the flame retardant comprises a phosphorus compound, for example, the amount of flame retardant added to each film layer may be about 5000 to 100,000 ppm, preferably about 5000 to 20000 ppm. In one particular embodiment, the amount of flame retardant added to each film layer may be about 8000 to 10,000 ppm.

FIG. 1 shows an embodiment of a three-layer composite film. However, it should be understood that an alternative embodiment may be a composite film consisting of only two layers, namely the first film layer 12 and the second film layer 14. In this embodiment, for example, the intermediate film layer containing the volatile decomposable flame retardant may be provided with a suitable coating for containing the volatile decomposable flame retardant. In certain embodiments, for example, a two-layer composite film may be laminated to another two-layer composite film and consist of two intermediate layers containing a volatile decomposable flame retardant.

  In some embodiments, the film layers can be coextruded together to form the composite film of the present invention. For example, the respective polymers or polymer blends used to form each layer are melted separately and extruded together but in multiple layers onto a mirror rotating film forming drum to form a multilayer film. The composite film is quenched and stretched in one or more directions to impart strength and toughness to the composite film. The composite film can be stretched uniaxially or biaxially, for example. Usually, stretching is performed between the second-order transition temperature of the polyester polymer and a temperature lower than the softening and melting temperature of the polymer. If necessary, the properties of the polyester film layer can be confined by subjecting the composite film to heat treatment after stretching to further crystallize the film. Crystallization imparts stability and excellent tensile properties to the composite film. Such heat treatment of the polyester film layer is usually performed at about 190-240 ° C. For example, in certain embodiments, the composite film can be exposed to heat at a temperature of about 215-225 ° C. for about 1-20 seconds, preferably about 2-10 seconds.

  The drawing ratio in drawing before heat treatment depends on various factors. In the case of uniaxial stretching, the film is stretched in a uniaxial direction (machine direction (longitudinal direction) or a direction perpendicular to the machine direction (transverse direction)) to about 1 to 4 times, preferably about 3 to 4 times the original length. I can do it. In the case of biaxial stretching, the film can be stretched in the transverse direction about 1 to 4 times, preferably about 3 to 4 times the original length.

  When the respective film layers are coextruded together, the intrinsic viscosity (IV) of the polymer resin used to form each layer can range from about 0.6 to 0.7I (IV). For example, the intrinsic viscosity of the polymer resin in each layer is about 0.61 to 0.63.

The final thickness of the composite film can vary depending on various factors and circumstances such as the manufacturing method used to produce the film and the field of end use. Generally, for example, the thickness of the composite film is from about 0.5 mil (about 12.7 μm) to about 7 mil (about 178 μm) or more. In certain applications, the thickness of the composite film is between about 1 mil (about 25.4 μm) and 2 mil (about 50.8 μm). In the above embodiment, the thickness of the second film layer 14 is typically about 0.5 to 1.5 (about 12.7 to 38.1 μm), for example.

Usually, the first film layer 12 and the third film layer 16 each occupy about 5 to 40%, preferably about 10 to 20% of the thickness of the composite film. In contrast, the second film layer 14 typically accounts for about 20-90%, preferably about 60-80% of the thickness of the composite film. In one particular embodiment, the first film layer 12 and the third film layer 16 each occupy about 15% of the thickness of the composite film, and the second film layer 14 is about the thickness of the composite film. It accounts for 70%.

  After production, the composite film 10 can be translucent, transparent, or opaque. For example, in one embodiment, each film layer can be formed from a thermoplastic resin containing a flame retardant to form a transparent composite film. However, in certain embodiments, it may be desirable for one or more film layers to be translucent or opaque. For example, in certain embodiments, the composite film can be dyed using, for example, a dye soluble in glycol.

In still other embodiments, one or more fillers can be included in the first film layer 12 and / or the third film layer 16 to color the composite film or make the composite film opaque. . The content is, for example, titanium dioxide particles, metal oxide particles, carbon particles and the like. The shape of the filler can be plate, rhombohedral, or circular. In general, an appropriate filler may be added to the film layer to impart an appropriate color to the composite film. The composite film can be colored, for example, white, black, gray, or any other suitable color.

When the filler is contained in the first film layer 12 or the third film layer 16, the filler content is about 5 to 50% by weight of the film layer. For example, the filler content may be about 10 to 40% by weight, preferably 25 to 35% by weight of the film layer.

  In addition to the filler addition, the polymer film layer may contain other suitable additives. Examples of such additives include antioxidants, matting agents, fillers, antistatic agents and the like. In certain embodiments, particularly when the window treatment member is constructed using a composite film, for example, one or more outer film layers may contain a UV shielding agent.

  The composite film of the present invention can be utilized in a variety of different application fields that are almost infinite. For example, in some embodiments, a flame retardant composite film may be used as a label and may be used in the electronics field. When used in the electronic field, for example, it may be used for cable coating or electric wires. Furthermore, the film can be laminated to many different articles and parts. For example, the film can be suitably laminated to a metal such as a steel product. In some embodiments, for example, the film may be used coated as a flame retardant for building materials such as garage doors. As mentioned above, the composite film can be used to construct various windowing members. Examples of such a window processing member include a window shade and a blind.

  In addition to the three film layers shown in FIG. 1, the flame retardant composite film of the present invention may have various other film layers and coat layers. For example, when the composite film 10 is used as a label, an adhesive layer may be applied to one of the outer surfaces of the composite film. The adhesive applied to the composite film can be determined by the particular application of the label. In some embodiments, a flame retardant adhesive may be applied to the composite film.

  When the adhesive layer is applied to the composite film, a release layer may be used to protect the adhesive layer before use. In this case, a release layer made of paper or film having a low adhesion surface is disposed on the adhesion layer, and can be removed before use. In some embodiments, for example, the release layer comprises a sheet-like substrate having a silicon coating on one side.

  Further, in addition to the adhesive layer, in certain embodiments, a variety of different coating layers may be applied to the composite film to facilitate adaptation of the member with the printed film.

  Furthermore, in other embodiments, a metallized layer may be formed on the outer surface of the composite film. The metallized layer may be formed of, for example, a metal or a metal oxide. Formation of the metallized layer on the composite film, in one embodiment, first applies the coating composition to the composite film to improve the adhesion between the composite film and the metal layer or metal oxide layer. The coating composition is formed from, for example, phthalic acid such as isophthalic acid, a sulfomonomer, and a diol.

The metal layer or metal oxide layer (metallized layer) may be formed by, for example, a vacuum evaporation method. In this type of method, a vapor of metal or a stream of atoms is deposited on the dry coating by vacuum deposition. Preferably, it is carried out by heating the metal to a temperature higher than the melting point of the metal in a high vacuum of 10 ⁻³ to 10 ⁻⁵ torr so that the vapor pressure of the metal exceeds 10 ⁻² or a substance This is done by exposure to a bombarded ion stream due to movement of the metal or metal oxide by moving “sputtering”.

  By achieving the above conditions, the metal is vaporized or sputtered, and metal vapors or atoms are emitted in all directions. These metal vapors or atoms strike the film surface and condense, thereby forming a thin metal coating on the film. Metals that can be used in this method include zinc, nickel, silver, copper, gold, indium, tin, stainless steel, chromium, titanium, aluminum, and oxides thereof.

  The thickness of the metallization layer depends on the field of use and various other factors. In certain embodiments, for example, the thickness of the reflective coating can be less than about 1000 mm, preferably about 300-600 mm. In still other embodiments, the thickness may be less than about 100 mm.

  The metallization layer thickness and the type of metal used to form the coating may be determined by the field of use. In some embodiments, for example, a reflective coating can be formed on the composite film so that light does not pass through the film. In other embodiments, however, the metallization layer may be translucent.

  In certain embodiments of the present invention, the flame retardant composite film shown in FIG. 1 may be inserted into the laminate. In certain embodiments, for example, a laminate may be used to manufacture a window treatment member such as a window bride or window shade. FIG. 2 shows one embodiment of a laminate 20 made, for example, according to the present invention. Like numerals are used to indicate similar members or configurations. In this embodiment, the laminate 20 is obtained by bonding two flame retardant composite films shown in FIG. In other embodiments, however, the flame retardant composite film 10 of the present invention may be adhered to other films or substrates.

As shown in FIG. 2, the laminate 20 includes a first flame retardant multilayer composite film 10 that is bonded to a second flame retardant multilayer composite film 110. The first multilayer composite film is formed according to the present invention, and has a configuration in which the second film layer 14 is disposed between the first film layer 12 and the third film layer 16. Similarly, the composite film 110 has a configuration in which an intermediate layer 114 is disposed between the outer film layers 112 and 116. According to the present invention, the second film layers 14 and 114 contain a volatile decomposable flame retardant. The outer film layers 12, 16, 112 and 116 also contain a flame retardant. The composite film 10 is bonded to the second composite film via the adhesive 22. The adhesive 22 may contain a flame retardant.

  In the laminate 20 shown in FIG. 2, a metallized layer 24 may be further provided so as to form the outer surface of the laminate. In certain embodiments, for example, the metallization layer 24 may be made of aluminum.

  The laminate 20 shown in FIG. 2 is particularly suitable for manufacturing window processing members such as shades and blinds. In some embodiments, for example, the metallization layer 24 can be designed to be translucent while partially reflecting light. The second composite film 110 can be dyed to block most of the light coming into contact with the member or to be a filter while the entire product is still translucent. For example, in one embodiment, the laminate 20 may have a dark color such as dark gray as a whole.

  For example, FIG. 3 shows a window shade 30 made in accordance with the present invention. The window shade 30 includes a shade 32 formed from the laminate 20 shown in FIG. The shade 32 is connected to a cross member (header) 34. The header 34 may include a reel for moving the shade 32 up and down as desired by the user. The shade 32 shown in FIG. 3 can be configured to be translucent or opaque.

  FIG. 4 shows another embodiment of the window processing member according to the present invention. In this embodiment, the window treatment member comprises a vertical blind 40. The vertical blind 40 includes a plurality of individual blinds 42 made of a composite film according to the present invention. Each blind 42 is connected to a cross member (header) 44 and includes a mechanism for controlling opening and closing of the blind and / or rotation of the blind.

  The invention will be described in more detail with reference to the following examples.

Example 1:
The flame retardant composite film shown in FIG. 1 was constructed, and Underwriter's Laboratories Test No. The flame retardancy test according to UL94 was performed. The thickness of the composite film was 36 μm.

  The composite film consisted of three film layers. Each film layer consisted of a polyester polymer chemically modified with a flame retardant. The polyester polymer consisted of polyethylene terephthalate.

  Specifically, the composite film included two outer layers of polyethylene terephthalate resin sold by Invista as “VA09”. The polyethylene terephthalate resin contained an organic phosphate ester flame retardant. The flame retardant was bis (2-hydroxyethyl) [(6-oxide-6H-dibenzo- [c, e] [1,2] oxaphosphorin-6-yl) methyl] butanedicarboxylate. The concentration of flame retardant in the polymer was about 9000 ppm.

  The intermediate layer of the composite film was formed from a modified polyethylene terephthalate resin sold by Invista as “8934H”. The polymer resin contained a volatile decomposable flame retardant. The volatile decomposable flame retardant was a phosphorus compound ester. The concentration of the volatile decomposable flame retardant in the polymer was about 9000 ppm.

  The composite film was produced by the coextrusion method described above. The film was biaxially stretched during the manufacturing process.

  Submit the film to Underwriter's Laboratories and follow UL94, no. Eleven flame retardant tests were performed. The flame retardancy evaluation of the composite film was found to be VTM-0.

  These and other improvements and modifications of the present invention can be made by those skilled in the art without departing from the spirit and scope of the invention as set forth in more detail in the appended claims. Further, it should be understood that the subject matter of the various embodiments may be interchanged both in whole or in part. Further, those skilled in the art will appreciate that the above description is illustrative only and is not intended to limit the invention.

Claims (10)

The first and third film layers are composite films having a thickness of 1 to 2 mil disposed so as to sandwich the second film layer, and the composite films are coextruded and biaxially stretched. The second and third film layers are made of polyethylene terephthalate, the first and third film layers contain the first flame retardant, the second film layer contains the second flame retardant, and the first difficulty The flame retardant and the second flame retardant are each chemically bonded to the polyethylene terephthalate polymer, and the first flame retardant is bis (2-hydroxyethyl) [(6-oxide-6H-dibenzo- [c, e] [1, 2] oxaphosphorin-6-yl) methyl] butanedicarboxylate, the second flame retardant is a phosphorus compound ester, and the weight of the second film layer is 60 to 8 of the weight of the composite film. Percent by weight, the flame retardant composite film evaluation in accordance with UL-94 test method is a VTM-0. The flame retardant composite film according to claim 1 , wherein the first flame retardant and the second flame retardant are incorporated in the main chain of the polyethylene terephthalate polymer . The flame-retardant composite film according to claim 1 or 2 , wherein the content of the phosphorus compound contained in the first film layer, the second film layer, and the third film layer is 5000 to 20000 ppm. The weight of the first film layer is 10 to 20% by weight of the weight of the composite film, and the weight of the third film layer is 10 to 20% by weight of the weight of the composite film. The flame retardant composite film described. The flame-retardant composite film according to claim 1, wherein the first film layer contains a filler for coloring the layer. Furthermore, the flame-retardant composite film in any one of Claims 1-5 which has the metallization layer adhere | attached on the 1st film layer. The flame retardant composite film according to any one of claims 1 to 6, wherein the intrinsic viscosity IV of the polyethylene terephthalate polymer for forming the film layer is 0.6 to 0.68 . The laminated body which adhere | attached two flame-retardant composite films in any one of Claims 1-7 . The laminate according to claim 8 , wherein the laminate includes a first outer layer surface and a second opposite outer layer surface, and the first outer layer surface is a metallized layer. A window blind or sunshade comprising the laminate according to claim 8 .

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